Due to the increasing world population, the increasing energy demand and due to the international discussion concerning climate warming governments in various regions enforce the exploitation of regenerative energies. Before this background solar-thermal power plants in sunny regions in future are attributed a considerable share of the energy mix. Basically, many sunny regions are affected by water shortage. Thus it must be taken as a basis that solar-thermal power plants are often carried out with dry cooling and will thus directly be dependent on the surrounding temperature.
Generally in the thermal power plant-technique a difference is made between four various cooling methods:
1. The fresh water cooling uses cooling water from surface water, which can be redirected after the cooling-process.
2. With the cooling in wet-cooling tower the greatest cooling effect does not occur due to the surrounding air, but due to the evaporation process. Wherein, however, great water quantities are lost, for which reason this variation is not suited for regions with water shortage.
3. With the direct dry cooling the expanded water vapor in the condenser is condensed due to the direct cooling by means of air.
4. When a separate cooling cycle is present, then an indirect dry cooling is spoken of. Wherein the cooling water first of all extracts heat from the water vapor in the condenser and afterwards in the cooling-tower by means of the surrounding air is cooled again.
In regions with water shortage often direct or indirect dry-cooling systems are used with the surrounding air as the sole heat sink. The temperature of the cooling medium has a direct influence on the thermo-dynamic efficiency of a thermal power plant. In sunny, hot regions dry cooling thus directly leads to a reduced efficiency of the installed power plants. For this reason it is important to use a cooling-system getting along without nameable water losses as well as achieving an acceptable degree of efficiency in the water-steam-cycle of the power plant.
The mentioned principle-caused disadvantages of directly or indirectly air-cooled condensers with a power plant according to the invention are reduced by using the ground in the direct vicinity of the power plant as heat sink.